Curved extrusion earns top honors

An extruded aluminum roof rail for a Mercedes car took Grand Prize at a recent competition

sponsored by The Extrusion Technology for Aluminum Profiles Foundation, Wauconda, Ill. (www.etfoundation.org), and Hydro Aluminum North America, Linthicum, Md. (www.hydroaluminumna.com). The rail highlights a new “rounding” process developed by Erbsl^h AG in Germany, says judge Angel Rosario, Applications Engineer, Alcoa Engineered Products, Chicago (www.alcoa.com). The process reportedly generates curved, springback-free extrusions at the press. “This eliminates problems associated with bending extrusions including ‘orange-peel' surfaces, springback control, and grooves generated during cold working that need secondary finishing operations,” explains judge Joseph Benedyk, Research Professor, Illinois Institute of Technology, Chicago. The roof rails boast radii of 2.6 mm with tolerances of ±0.5 mm and are made from a 6060 agehardened aluminum alloy. The rails are laser welded in a secondary operation, get a proprietary KTL coating, and then laser marked with the Mercedes moniker.

The top Commercial prize went to an aluminum web plate used in building the New Wave Truss from Total Structures Inc., Ventura, Calif. (www.totalstructures.com).

“Aluminum web plates are a great extrusion application,” says Rosario. “The multivoid hollow extrusions hold the structural chords (tubes) of a modular truss/rigging system that goes together like an erector set.” The 6 3 6-in. extrusion can be anodized and custom cut to give an added punch to the look of trade-show booths and other rigging applications. Chord styles include aluminum, carbon fiber, and plexiglas.

Sudal Industries Ltd., India, (www.sudalindustries.com), took Industrial honors for a 7-kg end cap for a uranium rod holder used in nuclear-power plants. The six-void extrusion is made from a nonheat-treatable 5052 alloy. “Many manufacturers would refuse to process this alloy due to the complex shape. The part requires an extrusion ratio (area of billet/area of extrusion shape) of 9:1,” explains Rosario. With such a low ratio, extrusions can develop a course-grain structure that reduces mechanical properties if the extrusion process is not carefully controlled.

The Residential award was jointly given to the extruder and manufacturer of the Trans-Stand Free Standing Lift System. The lightweight lift is portable, reportedly letting one person lift a disabled individual weighing up to 400 lb. The assembly is a perfect fit for an aluminum extrusion, states Joe Jackman, spokesman for the Ontario-based extruder Almag Aluminum Inc. (www.almag.com.) Engineers at Waverly Glen Systems Ltd., Concord, Ontario (www.waverleyglen.com), designed the lift which requires extremely tight tolerances so the trolley runs seamlessly between each mating profile as the person is moved from bed to wheelchair. “Tight tolerances also help ensure the structure is completely stable during use. 6005-aluminum alloy provides the needed strength, yield, and surface finish required,” says Jackman.

Kaiser Aluminum, London, Ontario (www.kaiseral.com), took Transportation honors for rear-suspension links used on Lincoln Town Cars. According to Kaiser's John Vanderzyde, two 6061-T6 multivoid hollow extrusions are friction stir welded together. This provides a 27% drop in weight compared to its steel predecessor build from a three-piece assembly needing two welding operations. “The extruded part has higher tensile and fatigue strengths that give the new suspension equivalent or improved performance at a lower production cost,” says Vanderzyde.